Southern California air regulators issued violations to two foundries in southeast Los Angeles County after air sampling revealed elevated levels of a highly toxic metal near the facilities.
Air samples collected Sept. 10-22 in the city of Paramount had “slightly elevated” levels of hexavalent chromium, according to the South Coast Air Quality Management District. Federal and state regulators have found in the past that the chemical compound is a potent carcinogen with no safe level of exposure.
The samples that led to the violations were collected at a city-run monitoring station near Minnesota Avenue and Madison Street, prompting the air district to launch an investigation and conduct inspections at several industrial facilities nearby.
On Friday, the air district announced that it handed down multiple air-quality violations to Pro Cast Industries, located across the street from the monitoring station, and Fenico, about 1,300 feet east.
Hexavalent chromium, commonly known as chrome, is best known for providing shiny, rust-resistant coating to auto parts, aviation components and tools. Foundries, which liquefy and cast metals, can release hexavalent chromium during melting, welding and grinding.
The heavy metal is 500 times more carcinogenic than diesel exhaust and poses the second-highest cancer risk of all toxic air contaminants tracked by the state, according to the California Air Resources Board. Only dioxins, which come primarily from burning waste materials, are deadlier than airborne hexavalent chromium.
When it comes to the latter, exposure to 1 nanogram per cubic meter for 30 years is associated with a cancer risk of 360 cases in 1 million people, according to a state report. Three air samples collected last month at the Paramount monitor found levels between 1.6 to nearly 2.2 nanograms per cubic meter.
Investigators allege both foundries in Paramount failed to conduct tests to ensure compliance with hexavalent chromium emission limits, did not properly clean areas near chrome-alloy-melting facilities and operated equipment without necessary permits.
Pro Cast was also cited for using more chromium-containing metals than regulators had approved for its processes, and for improperly storing scrap metal that contained chromium.
Pro Cast and Fenico representatives did not respond to The Times’ request for comment.
The air district said that it may seek a settlement with the two foundries, but if one is not reached, it may assess financial penalties.
“We’re working diligently to ensure the air in our city remains safe for all our residents. The South Coast AQMD has the expertise and enforcement tools to investigate and address these readings,” Mayor Peggy Lemons said in a statement last week. “The city is deeply committed to keeping our community informed and working collaboratively with the air district to ensure our residents’ health and safety.”
Paramount is home to dozens of metal-related businesses, which have historically contributed to some of the state’s highest concentrations of hexavalent chromium, including a spike of 26 nanograms per cubic meter in late October 2016.
The air district initially launched a community air monitoring network for hexavalent chromium and other toxic air contaminants in Paramount in 2013, after residents complained about metallic odors near a metal forging and grinding operation.
Air sampling in 2016 revealed that some parts of Paramount were exposed to levels more than 50 times higher than in other areas of Los Angeles County, according the county Department of Public Health. Investigations and inspections of these facilities have reduced levels of toxic metals since then.
Nevertheless, air sampling has continued to find troubling levels of toxic metals after equipment malfunctions, repairs and noncompliance with regulation.
